import numpy as np
import pandas as pd
a = np.array([[1, 2, 3], [4, 5, 6]])
b = np.array([[20, 30], [11, 22], [33, 44], [55, 66]])
# 将NumPy数组转换为Pandas DataFrame
df_a = pd.DataFrame(a, columns=['col1', 'col2', 'col3'])
df_b = pd.DataFrame(b, columns=['col1', 'col2'])
# 使用concat函数合并DataFrame
result = pd.concat([df_a, df_b], axis=0)
print(result)
结果: